Universal modular printed circuit magnetic reed keyboard switch assembly

ABSTRACT

At least one glass tube enclosed magnetic reed switch is mounted on a planar printed circuit board which is removably inserted into a hollow housing member in grooves on either side of an axially movable planar key member with a magnet thereon actuating the switch contacts during a limited range of movement. This provides a universal mounting arrangement wherein one to four switches and other circuit elements may be located upon the printed circuit cards for operation by a single manually depressed key at one or more positions of its stroke. Each switch is standardized for predetermined operation timing during the magnet movement by selectively bending the leads and inserting into registration apertures in the printed circuit boards. The switch is thus precisely located within the magnetic field by simplified structure affording strain relief at closed ends of the glass tubes. The leads are bent normal to the reed switch axis for this purpose at calibrated positions to thereby precisely locate the magnetic switch gaps by means of punched hole pairs easily located to close tolerances in the printed circuit board.

Imited States Patent Peroni et a1.

[4 1 May 23, 1972 [72] Inventors: Peter A. Peroni, Pottstown; John PaulJones, Jr., Wayne, both of Pa.

Navigation Computer Corporation, Norristown, Pa.

[22] Filed: 'Aug. 14,1969

[21] Appl.No.: 850,100

[73] Assignee:

Related US. Application Data [62] Division of Ser. No. 678,336, 0 26,1967, Pat. No.

[52] US. Cl ..29/622, 29/624, 29/626, 29/593, 29/407 [51] Int. Cl...H01h 11/00 [58] Field of Search ..29/622, 203 B, 407; 335/15l154, 206;140/105; 227/90; 317/101 C [56] References Cited UNITED STATES PATENTS2,902,691 9/ l 959 Kwasniewski ..29/509 2,978,707 4/1961 Runciman...29/203 B 3,167,780 2/1965 Mueller ..227/90 X 3,215,794 ll/l965Zielinski..... 317/101 C X 3,268,686 8/1966 Waver.... ..335/1543,222,758 12/1965 Marks ..29/622 X Primary Examiner.lohn F. CampbellAssistant Examiner-Robert W. Church Attorney-Laurence R. Brown ABSlRACTAt least one glass tube enclosed magnetic reed switch is mounted on aplanar printed circuit board which is removably inserted into a hollowhousing member in grooves on either side of an axially movable planarkey member with a magnet thereon actuating the switch contacts during alimited range of movement. This provides a universal mountingarrangement wherein one to four switches and other circuit elements maybe located upon the printed circuit cards for operation by a singlemanually depressed key at one or more positions of its stroke. Eachswitch is standardized for predetermined operation timing during themagnet movement by selectively bending the leads and inserting intoregistration apertures in the printed circuit boards. The switch is thusprecisely located within the magnetic field by simplified structureaffording strain relief at closed ends of the glass tubes. The leads arebent normal to the reed switch axis for this purpose at calibratedpositions to thereby precisely locate the magnetic switch gaps by meansof punched hole pairs easily located to close tolerances in the printedcircuit board.

2 Claims, 9 Drawing Figures la n J! Patented May 23, 1972 2 sheets sheetl INVENTOIS PETER A PERONI JOHN PAUL JONES, JR.

ATTORNEY Patented May 23, 1972 3,6fi4h014 2 Sheets-Sheet 2 l8 0 16B 45 ra M j 1 D 78 MAGNET IOA l6 1 I08 I4 I NV ENTORS PETER A PERONI JOHN PAULJoNLgJH.

ATTORNEY UNIVERSAL MODULAR PRINTED CIRCUIT MAGNETIC REED KEYBOARD SWITCHASSEMBLY This is a divisional application of U.S. Ser. No. 678,336 filedOct. 26, 1967, U.S. Pat. No. 3,462,719, granted Aug. 19,

This invention relates to keyboard switching apparatus and manufacturingmethods. More particularly, it relates to switch mounting assembliescontaining one or more glass enclosed magnetic reed switches operated bya magnet moved adjacent thereto.

This general type of keyboard switch together with attendant problemsand features of operation is known in the art as may be seen from U.S.Pat. Nos. 3,251,962 J. P. Jones, Jr., and 3,311,210 P. Peroni. However,certain problems and deficiencies exist in prior art switches of thistype, particularly in view of demand for various complex configurationsof switching contacts and conditions in electronic keyboard operatedequipment such as computers and control systems. For example, it hasbeen difficult in the prior art to operate uniformly in a singlestandardized mounting arrangement a plurality of as many as fourswitches which may be connected in completely isolated circuits tooperate at similar or different timing under control of a single movingmagnet. Also, interference problems can exist when a large number ofswitches are mounted close together on a keyboard so that they come nearthe magnetic fields of magnets moving in adjacent switches.

In addition, mounting and disassembly techniques are important, not onlyfor ease of manufacture, and repair, but for reliability. Thus, themounting of a tubular glass enclosed reed switch can provide stresses onthe glass causing failure or abnormal contact resistance and bounce.

1n switches of this class using moving magnets, care must be taken inprecise location of the magnetic gaps in the reed switches relative tomovement of the magnet, particularly if two separate reeds need beactuated substantially identically at the same time or at preciselyspaced stroke intervals where the magnet position cannot be adjusted tocompensate for differences in position. Also, differences in spacing ofthe reeds from the axis of the magnet are important as well as thespacing of the switch gaps along the axis, and precise but inexpensiveswitch locations means has not heretofore existed.

Thus, it is an object of this invention to produce an improvedmagnetically operated switch which can precisely and uniformly operate aplurality of isolated contacts.

It is a further object of the invention to provide magnetic switches andmanufacturing methods for establishing uniformity of response fromswitch to switch when multiple switching sets are operated by a singlemagnet.

A still further object of the invention is to provide improved switchhousing universal in nature for holding modular inserts for varioussemicustom switch configurations.

Thus, there is provided by the disclosed embodiment of the invention amagnetic switch assembly including a substantially cubic hollow housingwith three grooved slideways to accept and register in removableposition two planar printed circuit boards and a movable magnet assemblywithin the housing. The printed circuit boards may be mountedsymmetrically on both sides of the magnet assembly in grooves whichprecisely locate the circuit board positions. The board itself may haveaffixed thereto one or more magnetically operated reed switches whichare actuated by the movement of a magnet held in an assembly positionedtherebetween to slide in a further precisely located groove whichdefines the magnet axis and degree of movement. The reed switchesenclosed in glass envelopes have their leads bent normally to their axisto precisely locate the position of the gap along the 'axial movement ofthe magnet. These are spaced in apertures punched in the printed circuitassembly within very close tolerances both with respect to spacing fromthe magnet and along its axial movement path. Furthermore, this providesa mounting with strain relief at the ends of the reed switch glasstubes, since extreme pressures or strains from temperature damages orshocks are absorbed in the elastic leads, which suspend the switch andeliminate any stiff mounts near the glass tube.

The preferred embodiment of the invention is described in more detailwith reference to the accompanying drawings, wherein:

FIG. I is a partially cut away perspective view of a keyboard switch andhousing assembly embodiment provided by the invention;

FIG. 2 is a perspective view of the switch housing looking into the topopening;

FIG. 3 is a side view in section of the switch housing;

FIG. 4A is a plan view of a removable modular printed circuit switcharray provided by the invention and FIG. 4B is a variation;

FIG. 5 is a side view, partly in section, of a movable magnet keyingassembly;

FIG. 6 is a simplified top section view of two side-by-side switches asarranged in a keyboard; and

FIG. 7A is a sketch illustrating the standardization procedure forlocating switches in the key switch assembly of the invention with FIG.78 showing a variation.

As may be seen from FIGS. 1 to 3, a substantially cubic thinwalledhollow housing 10 is provided from a suitable plastic material. Thehousing 10 has on its internal walls a set of three pairs of grooves 11,12, etc. for receiving a magnet holding key assembly 14 (seen in FIG. 5)in the central groove pair sandwiched between two planar printed circuitcards 15 (seen in FIG. 4). Each printed circuit card has mounted thereonone or more glass enclosed tubular magnetic reed switches 16 by means ofregistering bent leads extending axially from each end into preciselyspaced apertures l7, 18, etc. in the printed circuit boards 15. A cap 20is frictionally held in registering grooves 19 in the top opening of thehousing to retain the printed circuit cards 17 and key assembly afterinsertion into grooves 11.

The bottom of the housing 10 is closed and stiffened with braces 21, andis slanted for mounting in a keyboard arrangement on a sloping laminatedprinted circuit wiring panel 22 with registration tab 23 locating thehousing in aperture 24 of the panel 22. Apertures (not shown) in thepanel register with the extending circuit connectors 25, 26, 27extending from the switch mounting cards 15, so that they may beprocessed by dip soldering for example, to join to a wiring panel in thecooper lamination 28 of panel 22. The switch housing 10 may be afiixedin place by a screw 29 registering in aperture 30 coaxially centeredwithin boss 31 at the bottom of the housing. An arrangement for mountingon the sloping panel as described in the hereinbefore mentioned Peronipatent may be used if desired. A coiled spring 32 seated about boss 31engages the movable key assembly 15 to bias it upwardly with shoulder 33resting against the cap 20. When the key cap 34, frictionally fit uponshaft 35 extending externally from the housing 20, is depressed againstthe bias of spring 32, the bottom prongs 35 of the key assembly 14strike the bottom of housing 10 to limit the motion or keystroke over apredetermined range.

A magnet 36 is held centrally in the key assembly in a position whichmoves therewith to operate the contacts of the surrounding magnetic reedswitches 16 somewhere in the range of motion of the,keystroke. Forpurposes of precisely positioning the magnetic action of this stroke themagnet may be frictionally held for movement in the manner described inthe hereinbefore mentioned Jones patent. For example, if the keyassembly is made of plastic, it may have frictionally engaging tabs 40holding magnet 36 but permitting longitudinal movement under force of acalibration instrument as shown in FIG. 5. If the key assembly (as shownin FIG. 6) is made of ferrous shielding material, then a brass clip 41may be affixed thereto for retaining magnet 368 in a frictionally heldlongitudinally movable position. If only one switch card 15 is included,this mounting may be desirable since a shield is introduced to preventinteraction of the magnet with switches in an adjacent keyboard switchassembly when switches are mounted closely together. Otherwise, thecentral positioning of the magnet 36A puts it in the most remoteposition and is desirable because four switches 16 on circuit cards 15Aand 158 can be symmetrically arranged for identical switchingcharacteristics under the influence of movable magnet 36A.

As shown in FIG. 4, switching, phasing, time or position in the switchelements 16A and 16B may be chosen for make-before-make sort ofswitching requirements, simply by staggering the mounting of theswitches in different mounting holes, 17 and 18, for example. Thus, theoverlapping reeds of the switches are at two different levels 45, 46 andthe magnet operates them at different positions along its movablestroke. Wiring patterns are shown on both FIGS. 4A and 43 to show wiringvariations and terminals of either printed circuit type 25, 26, 27 or ofextending wire type 25', 26', 27.

This switching feature can be coupled with a second heavier coil spring48 or equivalent leaf spring 48 as shown in FIG. 5, which is engagedafter a part of the key stroke to give a manual feel and provide adouble-action key where increased key pressure can provide a secondfunction in a completely isolated switching circuit after the firstcircuit is switched. For ready assembly of spring 32 inside the housingto slip over boss 31, it may be frictionally retained on a groove 49 intab 50 before assembly.

In this improved switch arrangement where it is desirable to operate aplurality of switches from a single magnet to provide complex switchingfunctions in isolated circuits, it is sometimes necessary to operate theswitches at close phasing. For example, it is desirable on a typewriterkeyboard to have all keys operated at the same stroke depth. Also, someelectronic circuits may require substantially identical timing of theswitch closures in two or more reed switch assemblies 16. As may bevisualized in FIG. 6, part of this problem is related to the spacing ofthe magnet from the switches, and the concentric arrangement ofsymmetrically positioned switches around centrally located magnet 36Apermits standardization of switch operation position within a smalldegree of error. In this respect accuracy of switching is possible withthe precise location of apertures 17, 18, etc. in switch mounting boardwhen the procedure described in connection with FIG. 7 is followed. Inthe described switches, magnetic reeds are sealed within a tubular glassenvelope and the leads 55 and 56 axially extend therefrom. A visualinspection readily shows the nominal location of the overlap section 54which can be gauged for positioning in a jig at marks 59. Then by use ofsimple fixed anvil 57 and movable brake 58 over a reciprocal motioncycle indicated at 60, the leads are bent into positions 55A and 56A.Thus, the switches are calibrated for the predetermined switchingtiming, location or sequence by selection of the desired standard leadconfigurations and matching holes l7, 18 to provide a whole seriesofmodules for diverse switching requirements.

Note that stresses at the glass seals are not great when mounted inprinted circuit cards 15 as compared with the holding ofa switch inposition in a switch by means of one lead extending through the bottomof the switch housing. Also note that the bending configuration of FIG.7A provides for lead bending without stress at the glass to metal sealwhere the leads leave the tube, when clamps 62 hold the leads tightbefore anvil 58 is moved.

As shown in FIG. 7B, the leads are preferably bent in relation to afixed test magnet which provides for closure of the contacts whenpositioned a variable distance a from one anvil. This permits individualswitch assemblies ofiering different characteristics to be made uniformwith respect to movement of magnets along the switch axis.

It is clear therefore that the present invention provides a modularkeyboard switch housing offering improved and advantageous features.Thus, a large range of custom switching configurations may be assembledwith standard modules. and the printed circuit mounting arrangementfurther increases life and reliability of the switches. Having thereforedisclosed a novel multiple purpose universal switch assembly wherein asingle movable magnet may precisely operate a multiplicity ofsurrounding switches, those features of novelty believed descriptive ofthe spirit and nature of the invention are defined with articularity inthe algpended claims.

W AT IS CLAIMED 1. The method of establishing a standardized switchingposition of at least one magnetic reed switch taken from a group ofswitches of varying characteristics, said switch constructed with leadsextending axially from a set of contacts through opposite ends ofatubular glass enclosure, wherein said switch is operated to switch at apredetermined position of a magnet movable over a limited rangealongside the axis of said leads comprising the steps of:

gauging accurately a gauged position on each lead extending from theswitch contacts,

bending the two leads of the switch to make a reference marker while atsaid gauged position to provide means for mounting the switch in areferenced position, establishing a set of registration apertures in acircuit board positioned to receive the bent leads, and affixing theswitch in a standard position in the circuit board through the aperturesby extending the bent leads therethrough,

mounting the switch adjacent said magnet range in a station positionfixed relative to the axis of the switch by said reference marker on thelead, and

moving the magnet in said range adjacent said switch at a distancetherefrom causing the reed to switch at a predetermined standardposition of the magnet in the range.

2. The method defined in claim 1, including the step of mounting twoswitches on a circuit board in apertures positioned relative to themagnet range so that the magnet operates the switch contacts of therespective switches at different positions in the range.

1. The method of establishing a standardized switching position of atleast one magnetic reed switch taken from a group of switches of varyingcharacteristics, said switch constructed with leads extending axiallyfrom a set of contacts through opposite ends of a tubular glassenclosure, wherein said switch is operated to switch at a predeterminedposition of a magnet movable over a limited range alongside the axis ofsaid leads comprising the steps of: gauging accurately a gauged positionon each lead extending from the switch contacts, bending the two leadsof the switch to make a reference marker while at said gauged positionto provide means for mounting the switch in a referenced position,establishing a set of registration apertures in a circuit boardpositioned to receive the bent leads, and affixing the switch in astandard position in the circuit board through the apertures byextending the bent leads therethrough, mounting the switch adjacent saidmagnet range in a station posiTion fixed relative to the axis of theswitch by said reference marker on the lead, and moving the magnet insaid range adjacent said switch at a distance therefrom causing the reedto switch at a predetermined standard position of the magnet in therange.
 2. The method defined in claim 1, including the step of mountingtwo switches on a circuit board in apertures positioned relative to themagnet range so that the magnet operates the switch contacts of therespective switches at different positions in the range.